From Real Goods, who’ve been doing the sustainability thing for almost 30 years:

We generally advise that a good year-round wind turbine site isn’t a place that you’d want to live. It takes average wind speeds of 8 to 9 mph [3.6-4 m/s, or 12.9-14.5 km/h] and up, to make a really good site. That’s honestly more wind than most folks are comfortable living with.

Congratulations are due to Glen Estill, who got his two Vestas V82s on the Bruce Peninsula running today. Glen is a pioneer of wind energy in Ontario, and we’re all grateful to him for his tireless work for the industry.

Heartlands; a fine British romantic comedy, in that it’s neither particularly romantic, nor particularly funny. It’s a meandering vision-quest on a Honda C50 by a lovelorn darts-obsessed newsagent. But it’s got music by Kate Rusby, and Royd Moor wind farm makes a guest appearance, so it’s okay by me.

It really annoys me that Natural Power Consultants have been so quiet about a blade failure at Crystal Rig. Not merely has it taken them two months to start repairs, but they haven’t come out with a news release saying what happened, how unlikely it is to happen again, and reassuring everyone that this is a) very unusual, and b) fully under control.

Wind farm operators aren’t alone. The actions of one in one country affects the industry worldwide. I mean, we’re even seeing questions in Ontario based on the Altamont experience. So, c’mon people, get hep.

So I download the very pretty PDF spec sheet. Here’s the technical table from the document, which is dated 19 November 2004:
So that’s a diameter of 2m, rated wind speed of 10.5ms-1, and a rated power of 1.5kW. Plugging that into my simplified Cp equation

Cp = P / ( 0.48106 d2 v3 )

which gives:

Cp = 1500 / ( 0.48106 × 22 × 10.53 ) = 0.67

As this is higher than the Betz Limit of 0.59, the claimed power output of the Swift wind turbine is theoretically impossible.

I don’t know how to put this, but rooftops are sheltered places; if they get any wind at all, it tends to be turbulent and highly directional. You get huge updrafts, none of which help generate power. I know of some very open sites that struggle to get the 3.5ms-1 cut-in speed of the Swift, and that speed is at 50m+, not on a rooftop.

Renewable energy, for me, is about using the appropriate technology for the right location. Devices like the Swift are a distraction from the whole conservation/renewables agenda.

Someone commented here that one could build such a device cheaply from parts from any DIY store. This isn’t quite the case. Properly formed blade sets are not trivial to make, and while you could build your own generator, weatherproofing it and making it CE-compliant would be hard.

wind-farm.org, however, is a hilarious mess of nonsense. It has been put together by a very few antis who managed to scrape up hosting and a CMS package. They also use that Never doubt that a small group of thoughtful, committed citizens can change the world… Margaret Mead quote that coincidentally appears on many pro-renewables sites. I’m half tempted to post to the forums under an assumed name, but I’m minded what Big Fred N. said: Battle Ye Not With Monsters, Lest Ye Become A Monster.